Motor spirit containing metallo organic catalyzers and self-made antiknocking compounds and process of making same



Patented July 19, 1932 UNITED STATES'PATENT OFFICE CARLETON' ELLIS, 0F MONTCLAIR, NEW JERSEY, ASSIGNOR TO ELLIS-FOSTER COI- PANY, A CORPORATION OF NEW JERSEY MOTOR SPIRIT CONTAINING METALLO ORGANIC CATALYZERS AND SELF-MADE ANTI- KNOCKING COMPOUNDS AND PROCESS OF MAKING SAME No Drawing.

This invention relates to a motor fuel or motor spirit containing certain compounds modifying the combustion characteristics of the fuel when employed in internal combusti on engines.

One object of the invention is to obtain a motor fuel which is free from that form of detonation known as knocking when relatively high compressions are employed or when the fuel contains too large a proportion of heavier constituents.

In one phase of the invention it is a particular object to obtain by the chemical treatment of the motor spirit itself certain bodies or compounds which prevent knocking. Such compounds are of petroleum derivation and are made by reacting on the constituents of the motor fuel or spirit and especially on cracked gasoline more particularly that made by pressure cracking of heavier oils and known as pressure still gasoline with certain reagents such forexample as nitric acid to obtain various chemical derivatives effective for the purpose in hand.

An advantage of the embodiment of the invention referred to above is the cheapness with which the required constituents may be obtained. Instead of being obtained by elaborate processes through other channels the compounds requisite for the purpose may be obtained in a petroleum refinery and in a simple manner.

The pressure still motor fuel which I prefer to use is that which is obtained by cracking heavier oil at pressures ranging tion if desired, with the chemical reagent em- Application filed September 29, 1924. Serial No. 740,622.

ployed herein, or the fuel may be fractionated to eliminate the very light or'semi-gaseous products on the one hand and the heavier oily fractions on the other. Whichever part or fraction of the material is used will be found to contain the cyclicized and also unsaturated compounds referred to above and many of these have very pronounced chemical activities. One reaction which is of importance in the present invention is that of the action of nitric acid or a nitrating agent such for example as a mixture of nitric and sulphuric acids, or of sulphuric acid and sodium nitrate on these pressure still distillatcs. Nitro compounds are obtained as well as certain other products of oxidation which are of value in engine fuels and which in part at least may be readily reduced by the action of nascent hydrogen to give amino or amido bodies and the like which have characteristic anti-knocking qualities.

The distillates may be treated with a small amount of strong nitric acid to bring about nitration and subsequently exposed to the action of a mixture of dilute sulphuric acid and iron scrap to form amines etc.

In one form of the operation the distillate which is to be refined by treatment with sulphuric acid may be simultaneously nitrated by adding a small proportion of strong nitric acid to the sulphuric acid refining agent. The mixed acids may be agitated with the motor spirit to simultaneously effect purification and nitration. This may be followed by reduction for example by means of dilute acid and iron scrap or filings to yield nascent hydrogen. Or zinc dust or aluminum scrap may be added to the caustic soda treatment to bring about reduction to amines while the motor spirit is being subjected to the usual alkaline wash.

While I do not Wish to limit myself to the last mentioned procedure it is preferred because of the fact that it does not greatly increase the steps required in the refining process.

Otherwise when it is possible to carry out separate steps these may be performed as for example, 1, nitration; 2, sulphuric acid treatment; or on the other hand, 1, sulphuric acid treatment, and 2, nitration followed by reduction and alkaline treatment, desulph izing etc.

By cyclicizing petroleum-material 1s meant the treatment of crude petroleum or any suitable fraction thereof but more particularly heavier distillates to obtain therefrom a motor fuel or motor spirit of an appropriately volatile character containin an influential proportion of cyclic hy carbons preferably including those of the benzenoid and non-benzenoid series. By selectively cyclizing petroleum material ismeant that treatment which enables the production at will of larger or smaller proportions of benzenoid or non-benzenoid cyclic compounds of differing character, such alterations by this selective treatment being designed to yield fuels especially adapted for the purp ose in hand, e. g. the use in engines having high or low compression, the making of mixed fuels including the production of a volatile liquid fuel miscible with alcohol and other combustible liquids and in general to perform the operation of cyclicizing in such a preferential or selective manner that motor fuels of improved characteristics and greater adaptability are obtainable. v

As noted above partial oxidation may be carried out on the cyclicized material and this may be accomplished if desired by air oxidation. The invention is not however limited to the inclusion of this step but may be carried out without the employment of any oxidation treatment whatsoever other than that which might arise through the employment of nitric acid in carrying out the illustrative nitration step previously discussed.

The slight or partial oxidation referred to and which as an operation may be carried out simultaneously with the selectively cyclic izing step, or may be subsequent thereto or even in certain special cases may precede the step of cyclicizing, is primarily for the purpose of yielding a fuel which will burn with the minimum amount of separation of carbon and which therefore enables an engine to be operated for a longer period of time without the cleaning operation now customary. It offers thefurther advantage of yielding a cleaner fuel, that is one which burns with the production of less smoke and ill-smelling compounds. It may be observed that fuels containing benzol and similar aromatic hydrocarbons have a tendency to be smoky, that is to deposit carbon in the engine cylinders and to furnish a smoky exhaust. In the present invention even though asubstantial amount of benzolic or benzenoid hydrocarbons of smoky characteristics are produced by cyclicizing under selective conditions such an effect which maybe objectionable in many cases may be mitigated or largely or entirely overcome through the oxidation step. I

anaemia Thus the powerful propelling qualities of selected cyclic hydrocarbons obtained by the cyclicizing step may have any undesirable qualities counter-balanced or offset by the the present application ethyl alcohol may be looked upon as oxidized ethane. But ethane typifies a Series of hydrocarbons having smoke-forming and carbon-depositing properties. On the other hand the oxidized product, in this case ethyl alcohol, proves to be a clean fuel. By admixture of ethyl alcohol with a smoky fuel, such as benzol, fuels are obtained having improved combustion qualities.

Without offering the subject matter of the foregoing paragraph as an exact comparison I call attention to the possibility of adding oxygen to various hydrocarbons with the object of reducing their smoky qualities. Further there may be present from the cyclicizing step certain unstable bodies tending to resinify. For example cyclopentadiene may be present. This ordinarily would be removed by the usual sulphuric acid refining treatment. If however such crude or unrefined motor spirit is subjected to partial oxidation there exists the potential possibility of conversion of such unstable bodies into volatile combustible liquids adding to the yield of motor spirit rather than diminishing such yield as would be the case in the customary method of sulphuric acid refining.

In carrying out the oxidation step I preferably employ .a catalyzer such as-chromium oxide, vanadium oxide, iron chromate and similar oxidizing catalysts. If desired these may be placed on a support or carrier such as pumice. The catalytic material is placed in: a tube which is heated in a lead bath to 300 to 400 C. A temperature of 320 C. is ad:- vantageous. Uniform heating and heat control is quite essential to the successful operation of the process and consequently the temperature of the lead bath should be carefully watched. Likewise it is desirable to have a thermometer in the exit gases to indicate their temperature in order that the rate of flow of the gas through the catalyzing chamber may not be too rapid and thus cool the gases below a desirable oxidizing temperature. The air employed may be washed to remove impurities and may then be passed through a humidifier in order that the air may be saturated with a constant amount of moisture. The air is then fed into a vaporizing chamber into which the fraction of the oil which is to be treated is slowly introduced and on heating this chamber, when heat is required, vapors of the distillate are obtained admixed with air and are passed onward to the catalyzing chamber. The amount of oxygen introduced should be carefully proportioned, preferably about 20 per cent bein used but the proportion varying with di erent hydrocarbon mixtures. The exit gases may be treated in various ways, preferably they are passed through a cooling chamber in which are cooling coils and in this chamber any solid crystalline substances etc. will be deposited to a considerable extent. The vapors from the cooling chamber then may pass through an ordinary aircooled or water-cooled condenser and subsequently if desired may be passed over activated carbon or silica gel. Another and preferable method of procedure is to pass the gases into the cooling chamber to collect any organic acids and other very readily condensable substances and to pass the vapors through a scrubbing tower through which water is passed in order to collect watersoluble products of oxidation and finally to pass through a scrubbing oil or into a scrubbing tower to collect the gasoline and other water insoluble liquids. It may be added however that in the water scrubbing apparatus a considerable amount of hydrocarbon may condense and this may be suitably separated. Or the products of oxidation may pass into an air-cooled condenser then into a water-cooled condenser and finally may be scrubbed with heavy oil or may be passed over activated carbon or silica gel. By using an air condenser of large size clogging due to the separation of solld crystalline substances may be very largely avoided, the apparatus being cleaned from time to time. The aqueous solution will generally be found strongly acid due to the formation of water soluble organic acids by the oxidation. These include not only monocarboxylic acids of the acetic acid type but also dicarboxylic acids.

Cracking may be carried out in a tube and tank system involving a tubular heat- 45 ing coil over a grate or other heating means throu h which coil heavy petroleum oil is force under pressure at high rapidity and becomes heated to a cracking temperature.

The pressure preferably is above atmos- 50 pheric, ordinarily 3 or 4 atmospheres or more, or even 5 to 10 atmospheres. Still higher pressures, e. g., 10-20 atmospheres may be used'in some cases. As the oil in the heating coil is subjected to a strong heat its 55 flow should be rapid to prevent the deposition of carbon in the tubes. The velocity should be sufliciently great to exert a scouring action and maintain the carbon in suspension for subsequent deposition in a digest- 60 ing tank or chamber. The oil may flow di rectly through the coil into the latter or the oil may be caused to continuously circulate in the coil while shunting a part thereof continuously into the digesting chamber and re- 5 placing this material by forcing fresh oil into the coil. In any event the oil is discharged into the digesting tank or chamber in a highly heated state such that it is undergoing a cracking and cyclicizing] action.

The temperature may range etween say 400 C. and 900 0., the higher temperatures favoring the formation of cyclic bodies. On the other hand high temperatures and high pressures require special materials of construction to be suitably resistant. In most cases a compromise has to be made between the desired high temperatures and pressures in view of the need of utilizing equipment already in place. A. considerably higher temperature may be reached in the coil than is needful in the digesting tank. Thus in the coil the oil may be superheated so to speak, the temperature being above the normal cracking point which is desirable for the formation of cyclicbodies. The temperature in the coil preferably is above 500 C. Variation in the temperature enables cyclic bodies to be formed selectively for example a temperature of say 600 will yield a predominating amount of single ring hydrocarbons such as benzol, while a temperature of say 700 to 750 C. will yield a substantial" proportion of hydrocarbons of the naphthalene type. Of course the ratios between the kind of cyclic bodies formed varies to some extent not only with the temperature but with the nature of oils from different sources. But with any given oil the nature of the cyclicization may be governed in a general way by the foregoing rule.

The oil traversing the heating coil finally enters the digesting tank or chamber where the oil is allowed to stand in a heated state, preferably without supplying any additional heat, or any great amount thereofand during digestion various unsaturated bodies especially under a high pressure may unite to form cyclic compounds of value in motor fuels.

Oxidation may be conducted in the digestor especially when the operation is conducted under high pressure by the injection of air through a distributor at or near the bottom of the oil column. If the oil is sufficiently hot, as would be the case under normal conditions of operation, the oxygen of the air or whatever oxygen-containing gas is employed unites with various compounds present in the oil with partial combustion forming a variety of oxygenated compounds. The reaction is exothermic and the injection of air should be such that the temperature does not rise unduly. On the other hand the temperature should be such as to cause a fairly rapid union of the oxygen with thecracked and cyclicized products.

The material thus formed may be conveyed through a condenser in.which condensation may take place under pressure or at atmospheric pressure and by dephlegmation or in any other suitable way the product maybe split into fractions the more volatile portion of which constitutes one form of the motor spirit of the present invention.

The distillate obtained as above bg cracking or by the steps of cracking an oxidation, as the case may be, may then be refined by treatment. with strong sulphuric acid and from 10 per cent to an equal amount of concentrated nitric acid. It is desirable to have the distillate free from water before carrying out the sulphuric acid sludging treatment and the nitration ste simultaneously. The temperature during t e sludging and nitration may be from ordinary atmospheric temperatures and upwards. However a temperature such that the nitric acld has more of an oxidizing action than a nitrating action usually is not desired. The reduction to amines and the like may take place by simple agitation with dilute sulphuric acid and iron scrap or the more preferable step of using the caustic soda solution, ordinarily em-' ployed as a neutralizing and purifying wash, to serve in the present invention as the means for reducing the nitro compounds may be employed. This may be secured by adding a quantity of zinc dust to the caustic soda solution, agitating in contact with the pressure disillate and thereby obtaining reduction which does not need to be complete. The presence of a small amount of nitro compounds, especially those which are more dilficult of reduction in some cases may serve as a desirable component of the fuel to modify its characteristics. I

The refined or rectified material maybe blended if desired with various other hydrocarbons or combustible liquids such or ordinary natural gasoline, ordinary cracked gasoline, shale oil distillates, benzol, toluol, solvent naphtha, ethyl alcohol, acetone, ether, carbon bisulphide etc.

" It should be noted that a substantial degree of volatility is important and I prefer a product with a smooth distillation curve and one which is free from any heavy liquid or solid bodies interfering with free and smooth volatilization.

Still another phase of the invention is that of the preparation of various metallo organic compounds'which may be employed in the present motor fuel along with the amines, nitro bodies or whatever chemical products are produced in the distillate itself by chemical treatment and which tend to modify the combustion characteristics, such as reduction inthe engine knock. When the prodnets of oxidation contain certain organic acids it is possble for example'to make lead, mercury, chromium and other compounds therefrom which may be used as catalysts to prevent engine knock. In some cases lead or other metallic naphthenates may be employedtetrachloride.

casinghead naphtha,

neonate Various metallic chlorides such as those of antimony, arsenic, tin, chromium and mercury have the property of unitin with olefins, diolefins, acetylene compoun s and the like and some of the more soluble types may be employed to theextent of a fraction of a per cent more or less to assist in reducing engine knock.

Antimony chloride or butter of antimony may be employed in this way. Likewise chromyl chloride.

en using such metallo organic compounds frequently it is desirable to have a chlorine compound present in order to furnish hydrochloric acid to react with any metal'such as lead deposited in the engine and thereby keep the interior of the engine tree from metallic deposits.

It has been customary to use with for ex- 7 ample lead tetra ethyl the compound carbon This has the disadvantage of becoming acid in the presence of water causing gasoline to attack metals. When amino bodies such as are described above are used in conjunction with lead tetra ethyl and carbon tetrachloride a neutralizing efl'ect may be obtained so that the action of the carbon tetrachloride on the gasoline tanks of automobiles is diminished.

Arsenic trichloride also is reactive with certain of the constituents of cracked petroleum and the arsenic compound obtained may be employed under some conditions. It is not recommended for use as a motor fuel in automobiles but may be employed in stationary engines, the exhaust gases from which are carried away by a chimney or other suitable ventilating device. 1 Still another feature set forth in the present invention is that of the employment of chlorinated hydrocarbons such as chlorben- 201 or orthodichlorbenzol which are stable and do not become acid and which furnish hydrochloric acid as may be required to remove metallic coatings from engine cylinders. They are not open to the objection that carbon tetrachloride possesses of being unstable in the presence of moisture.

When compounds such as antimony or arsenic chloride react with unsaturated hydrocarbons to ly soluble in gasoline to be used as anti-knock catalysts it may be noted that the compounds produce compounds sufiicientobtained frequently will contain not only .type.

making anti-knocking compounds or catalysts, has many desirable qualities of cheapness and manner of operation. Thus constituents which have been prepared in this manner may be termed self-made and in the claims I make use of such terms as self-made, nitrogenous, anti-knock catalysts and like expressions to designate products of this As a rule they may be more particularly characterized by the fact that nitration gives rise to a rather complicated series of nitro bodies some of which are present only in very small quantities and which are reduced to amines etc. and thereby lend to the fuel by virtue of their diversity of constitution, boiling point etc. a desirable efiect all dependent on conditions of preparation and of combustion. The product therefore is dissimilar from anything which might be obtained by the addition of a chemical individual such as aniline to a cracked oil.

It is proposed in some cases to prepare lead soap such as lead oleate, stearate, naphthenate etc. also bismuth or other heavy metal compounds of a similar character, cakes of such material if desirable may be incorporated with orthodichlorbenzol or some other chlorine-containing compound and may be added to gasoline for example in the automobile fuel tank. Such material may take the form of cakes or sticks, tablets and the like, or it may be suspended in a bag in the tank. Or a fuel may be prepared in advance by dissolving lead stearate in very minute proportion, for example one-tenth of one per cent or less, in pressure still gasoline which may or may not be oxidized and which may or may not be treated by nitration and reduction as set forth above.

While I have given as an illustrative example the preparation of motor fuels containing self-made amines and the like I do not wish to be limited to this phase of the invention but desire to include more broadly those chemical methods of treating motor fuel or oxidized motor fuel with other reagents having a like or analogous effect to obtain self-made, anti-knocking compounds or catalyzers.

What I claim is 1. The process which comprises treat ng pressure still motor spirit with a nitrating agent whereby a portion of the constituents thereof are nitrated and reducing at least a. portion of the resulting nitro compounds to form amino or amido bodies whereby a motor spirit of modified combustion characteristics is secured.

2. The process which comprises treating pressure still motor spirit with a nitrating agent whereby a portion of the constituents thereof are nitrated and reducing at least a portion of the resulting nitro compounds to form amino or amido bodies whereby a motor spirit of modified combustion characteristics is secured and in incorporating catalytic roportions of a metallo organic compound avmg anti-knocking qualities.

3. The process which comprises treating pressure still oxidized motor spirit with a n1- trating agent whereby a portion of the constituents thereof are nitrated and reducing at least a portion of the resulting nitro compounds to form amino or amido bodies whereby a motor spirit of modified combustion characteristicsis secured.

4. The process which comprises treating pressure still oxidized motor spirit with a nitrating agent whereby a portion of the constituents thereof are nitrated and reducing at least a portion of the resulting nitro compounds to form amino or amido bodies whereby a motor spirit of modified combustion characteristics is secured and in incorporating catalytic proportions of a metallo organic compound having anti-knocking qualities.

5. The process which comprises treating pressure still motor spirit containing kerosene with a nitrating agent whereby a portion of the constituents thereof are nitrated and reducing at least a portion of the resulting nitro compounds to form amino or amido bodies whereby a motor spirit of modified combustion characteristics is secured.

6. The process which comprises treating pressure still oxidized motor spirit containing kerosene with a nitrating agent whereby a portion of the constituents thereof are nitrated and reducing at least a ortion of the resulting nitro compounds to orm amino or amido bodies whereby a motor spirit of modified combustion characteristics is secured.

7. The process which comprises treating pressure still oxidized motor spirit containing kerosene with a nitrating agent whereby a portion of the constituents thereof are n1- trated and reducing at least a portion of the resulting nitro compounds to form amino or amido bodies whereby a motor spirit of modified combustion characteristics is secured and introducing a small proportion of a metallo organic compound serving as an anti-knock catalyst.

8. The process which comprises refining pressure still motor spirit with a mixture of concentrated sulphuric acid and nitric acid.

9. The process which comprises refining pressure still oxidized motor spirit with sulphuric acid and nitric acid.

1O. The process of treating pressure still motor spirit which comprises freeing same from water, and then treating the water freed material with sulphuric acid and nitric acid.

11. The process of treating pressure still motor spirit which comprises subjecting the same to treatment with concentrated sulphuric acid and nitric acid at a temperature such that the nitric acid has more of an oxidizing action than a nitrating action.

12. In the process ofpreparing motor spirit containing anti-knock compounds, wherein caustic soda solution has been used as a neutralizing and purifying wash, the

step of adding zinc dust to the material containing caustic soda solution, whereby reduction is obtained.

13. Pressure still motor spirits containing artificially prepared amino bodies of petro- 10 leum derivation.

14. Pressure still oxidized motor spirit containing artificially preparedamino bodies of petroleum derivation.

15. Pressure still motor spirit containing self-made nitrogenous compounds and metal- 10 organic compounds serving as anti-knock catalysts.

16. Pressure still motor spirit containing kerosene and self-made nitrogenous antiknock catalysts.

17. Pressure still motor spirit containing kerosene, self-made nitrogenous anti-knock catalysts and oil soluble metallo organic compounds.

18. Pressure still motor spirit containing.

tetra ethyl lead and a small proportion of self-made amino bodies.

19. Pressure still oxidized motor fuel containing catalytic. proportions of lead tetra 80 ethyl and a larger proportion of self-made nitrogenous compounds possessing antiknocking qualities.

20. Pressure still oxidized motor fuel containing kerosene, catalytic proportions of lead tetra ethyl and a larger proportion of self-made nitrogenous compounds possessing anti-knocking qualities.

21. Pressure still motor spirit containing self-made amino bodies and a small amount so of nitro compounds.

22. Pressure still motor spirit containing a small proportion of self-made amino bodies, a metal compound yielding antiknock properties and a chlorinated hydrocarbon.

23. Pressurestill motor spirit containing a small proportion of self-made amino bodies, a metal compound yielding antiknock properties and a chlorbenzol.

to v CARLETON ELLIS. 

